Method and apparatus for restoring a joint, including the provision and use of a longitudinally-adjustable and rotationally-adjustable joint prosthesis

ABSTRACT

A joint prosthesis for mounting in a first bone and presenting a prosthetic joint surface for engaging an opposing joint surface of a second bone, the joint prosthesis comprising: 
     a sleeve which is adapted for partial disposition in an opening formed in the first bone; 
     a center adapter which is adapted for disposition within the sleeve; and 
     a prosthetic joint surface mounted to the center adapter; 
     wherein the disposition of the center adapter is adjustable, both longitudinally and rotationally, relative to the sleeve, so that the disposition of the prosthetic joint surface is adjustable, both longitudinally and rotationally, relative to the opposing joint surface of the second bone.

REFERENCE TO PENDING PRIOR PATENT APPLICATIONS

This patent application claims benefit of:

(i) pending prior U.S. Provisional Patent Application Ser. No.61/278,782, filed Oct. 10, 2009 by Barry T. Bickley et al. for METHODAND APPARATUS FOR RESTORING A JOINT, COMPRISING THE PROVISION AND USE OFA LONGITUDINALLY-ADJUSTABLE AND ROTATIONALY-ADJUSTABLE JOINT PROSTHESIS(Attorney's Docket No. SIM-6 PROV); and

(ii) pending prior U.S. Provisional Patent Application Ser. No.61/368,424, filed Jul. 28, 2010 by Barry T. Bickley et al. for METHODAND APPARATUS FOR RESTORING A JOINT, COMPRISING THE PROVISION AND USE OFA LONGITUDINALLY-ADJUSTABLE AND ROTATIONALY-ADJUSTABLE JOINT PROSTHESIS(Attorney's Docket No. SIM-8 PROV).

The two (2) above-identified patent applications are hereby incorporatedherein by reference.

FIELD OF THE INVENTION

This invention relates to medical procedures and apparatus in general,and more particularly to medical procedures and apparatus for restoringa joint.

BACKGROUND OF THE INVENTION

Joint replacement surgery seeks to replace portions of a joint withprosthetic components so as to provide long-lasting function andpain-free mobility.

During joint replacement surgery, one or more of the operative elementsof the joint are replaced by prosthetic components. More particularly,many joints (e.g., the hip, the shoulder, etc.) comprise aball-and-socket construction. During total joint replacement surgery,the head of the bone which provides the ball is replaced by a prostheticball-and-stem, and the portion of the bone which provides the socket isreplaced by a prosthetic cup, whereby to provide the prosthetic totaljoint. In a partial joint replacement surgery, only one of the operativeelements of the joint may be replaced, e.g., the head of the bone whichprovides the ball.

The present invention is directed to situations where the head of thebone which provides the ball is replaced by a prosthetic ball-and-stem,or where the head of the bone which provides the socket is replaced by aprosthetic socket-and-stem, as will hereinafter be discussed in furtherdetail. For convenience, the present invention will generally bediscussed in the context of replacing the head of a bone with aprosthetic ball-and-stem, although it should be appreciated that thepresent invention is equally applicable to situations where the head ofa bone is replaced by a prosthetic socket-and-stem.

In order to replace the head of a bone with a prosthetic ball-and-stem,the head of the bone is first distracted from its socket so as to exposethe head of the bone. Then an osteotomy is performed so as to remove theneck and head of the bone from the remainder of the bone. This actionalso exposes the intramedullary canal (sometimes hereinafter referred toas “the bone canal”) of the bone. Next, the proximal end of the bonecanal is prepared to receive the stem of the prosthesis. Moreparticularly, a rasp, reamer, broach, etc. is used to hollow out, cleanand enlarge the proximal end of the bone canal so as to create anelongated cavity which will receive the stem of the prosthesis. Finally,the stem of the prosthesis is inserted into the bone canal so that theball of the prosthesis is appropriately presented to the socket.

Typically, the ball of the prosthesis is manufactured separately fromthe stem of the prosthesis, with the ball component and the stemcomponent being united at the time of use, although it is also possibleto form the ball integral with the stem at the time of manufacture.

Furthermore, it should also be appreciated that, during the surgeryitself, it is common to temporarily position a selected trial stem inthe bone, attach a selected trial ball to the positioned trial stem, andthen temporarily reduce the joint so as to confirm the jointreconstruction before the actual prosthetic stem is secured in positionwithin the bone.

It will be appreciated that, when replacing the head of a bone with aprosthetic ball-and-stem, the surgeon must consider the position of theprosthetic ball relative to the socket, and that this must be done inboth longitudinal and rotational terms. Specifically, the surgeon mustconsider (i) the longitudinal position of the prosthetic ball relativeto the socket, and (ii) the rotational position of the prosthetic ballrelative to the socket. This is necessary because, if either thelongitudinal position or the rotational position of the prosthetic ballis “off” (i.e., mispositioned) vis-à-vis the socket, the ball will notseat properly in the socket and the prosthesis will not function asintended. As a practical matter, these positioning considerationsrequire that a large inventory of prosthetic devices, of differinglengths and with differing angular orientations, must be maintained sothat the prosthetic ball can be properly positioned in the patient.However, this is a costly requirement, and failures in inventoryre-stocking can result in cancelled surgeries.

SUMMARY OF THE INVENTION

The present invention addresses the aforementioned problems associatedwith the prior art through the provision and use of a novellongitudinally-adjustable and rotationally-adjustable joint prosthesis.

More particularly, the present invention comprises a new jointprosthesis for replacing the ball of a ball-and-socket joint. This newjoint prosthesis comprises (i) a sleeve which is adapted for dispositionin the intramedullary canal of a bone, (ii) a center adapter which isadapted for disposition within the sleeve, and (iii) a ball mounted tothe center adapter, wherein the disposition of the center adapter isadjustable, both longitudinally and rotationally, relative to thesleeve, so that the disposition of the ball is adjustable, bothlongitudinally and rotationally, relative to the socket.

Alternatively, the ball of the new prosthesis may be replaced by asocket, in order that the new prosthesis may replace the socket of aball-and-socket joint. In this case, the disposition of the socket isadjustable, both longitudinally and rotationally, relative to thesleeve, so that the disposition of the socket is adjustable, bothlongitudinally and rotationally, relative to the ball.

In one preferred form of the present invention, there is provided ajoint prosthesis for mounting in a first bone and presenting aprosthetic joint surface for engaging an opposing joint surface of asecond bone, the joint prosthesis comprising:

a sleeve which is adapted for partial disposition in an opening formedin the first bone;

a center adapter which is adapted for disposition within the sleeve; and

a prosthetic joint surface mounted to the center adapter;

wherein the disposition of the center adapter is adjustable, bothlongitudinally and rotationally, relative to the sleeve, so that thedisposition of the prosthetic joint surface is adjustable, bothlongitudinally and rotationally, relative to the opposing joint surfaceof the second bone.

In another preferred form of the present invention, there is provided amethod for restoring a joint, the method comprising:

providing a joint prosthesis for mounting in a first bone and presentinga prosthetic joint surface for engaging an opposing joint surface of asecond bone, the joint prosthesis comprising:

a sleeve which is adapted for disposition in an opening formed in thefirst bone;

a center adapter which is adapted for partial disposition within thesleeve; and

a prosthetic joint surface mounted to the center adapter;

wherein the disposition of the center adapter is adjustable, bothlongitudinally and rotationally, relative to the sleeve, so that thedisposition of the prosthetic joint surface is adjustable, bothlongitudinally and rotationally, relative to the opposing joint surfaceof the second bone;

forming an opening in the first bone;

deploying a sleeve in the opening formed in the first bone;

positioning a center adapter partially within the sleeve;

adjusting the longitudinal and rotational position of the center adapterwith respect to the sleeve; and

securing the center adapter to the sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will bemore fully disclosed or rendered obvious by the following detaileddescription of the preferred embodiments of the invention, which is tobe considered together with the accompanying drawings wherein likenumbers refer to like parts, and further wherein:

FIGS. 1-9 are schematic views showing various aspects of a firstembodiment of the present invention;

FIGS. 10-13 are schematic views showing various aspects of a secondembodiment of the present invention;

FIGS. 14-20 are schematic views showing various aspects of a thirdembodiment of the present invention;

FIGS. 21-25 are schematic views showing various aspects of a fourthembodiment of the present invention;

FIG. 26 is a schematic views showing various aspects of a fifthembodiment of the present invention;

FIGS. 27-29 are schematic views showing various aspects of a sixthembodiment of the present invention; and

FIGS. 30-36 are schematic views showing additional aspects of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed at a new joint prosthesis forreplacing the ball of a ball-and-socket joint. This new joint prosthesiscomprises (i) a sleeve which is adapted for disposition in theintramedullary canal of a bone, (ii) a center adapter which is adaptedfor disposition within the sleeve, and (iii) a ball mounted to thecenter adapter, wherein the disposition of the center adapter isadjustable, both longitudinally and rotationally, relative to thesleeve, so that the disposition of the ball is adjustable, bothlongitudinally and rotationally, relative to the socket.

Alternatively, the ball of the new prosthesis may be replaced by asocket, in order that the new prosthesis might replace the socket of aball-and-socket joint. In this case, the disposition of the socket isadjustable, both longitudinally and rotationally, relative to thesleeve, so that the disposition of the socket is adjustable, bothlongitudinally and rotationally, relative to the ball.

Looking first at FIGS. 1-9, there is shown a new joint prosthesis 5 forreplacing the ball of a ball-and-socket joint. Joint prosthesis 5generally comprises a sleeve 10 (FIGS. 1-3) which is adapted fordisposition in the intramedullary canal of a bone. Sleeve 10 generallycomprises an elongated body 15 having a central lumen 20 (FIG. 2) formedtherein, and terminating at its proximal end in a crown 25 having aplurality of peripheral detents 30 formed therein. A center adapter 35(FIGS. 1, 4 and 5) is adapted for variable disposition within, andextension out of, central lumen 20 of sleeve 10. The disposition ofcenter adapter 35 relative to sleeve 10 is adjustable, bothlongitudinally and rotationally. More particularly, center adapter 35comprises an elongated shaft 40 terminating in a head 45. Elongatedshaft 40 of center adapter 35 comprises a mount section 50 whichcomprises a plurality of horizontally-extending slots 55 and a pluralityof longitudinally-extending slots 60. A two-piece collar 65 (FIGS. 6 and7), having at least one longitudinally-extending internal rib 70 formedon at least one of the halves of the collar, and having at least onehorizontally-extending internal rib 75 formed on at least one of thehalves of the collar, and having at least one radially-projecting nib78, is selectively fitted about crown 25 of sleeve 10 and mount section50 of center adapter 35, as will hereinafter be discussed. Screws 80(FIG. 1) are used to selectively hold the two halves of collar 65together about crown 25 of sleeve 10 and mount section 50 of centeradapter 35.

On account of the foregoing construction, when the two halves of collar65 are loose, center adapter 35 is able to move both longitudinally androtationally relative to collar 65, and collar 65 is able to move bothlongitudinally and rotationally relative to sleeve 10, sincelongitudinally-extending internal rib 70 of collar 65 will not projectinto a longitudinally-extending slot 60 of center adapter 35, andhorizontally-extending internal rib 75 of collar 65 will not projectinto a horizontally-extending slot 55 of center adapter 35, andradially-projecting nib 78 of collar 65 will not project into aperipheral detent 30 of crown 25 of sleeve 10. However, when the twohalves of collar 65 are tightened about crown 25 of sleeve 10 and mountsection 50 of center adapter 35, the collar makes a binding fit with (i)center adapter 35, by virtue of the engagement of the collar'shorizontally-extending internal rib 75 with one of thehorizontally-extending slots 55 of the center adapter, and by virtue ofthe engagement of the collar's longitudinally-extending internal rib 70with one of the longitudinally-extending slots 60 of the center adapter,and (ii) sleeve 10, by virtue of the engagement of the collar'sradially-projecting nib 78 with one of the peripheral detents 30 oncrown 25 of sleeve 10. In this way, by appropriately loosening collar 65about crown 25 of sleeve 10 and mount section 50 of center adapter 35,the disposition of head 45 of center adapter 35 may be adjusted, bothlongitudinally and rotationally, relative to sleeve 10; and byappropriately tightening collar 65 about crown 25 of sleeve 10 and mountsection 50 of center adapter 35, the disposition of head 45 of centeradapter 35 may be fixed relative to sleeve 10.

Ball 85 (FIG. 8) is adapted to be secured to head 45 of center adapter35. By way of example but not limitation, ball 85 may include a stem 86for positioning in a recess 87 formed in head 45.

Accordingly, it will be appreciated that, in view of the foregoingconstruction, the disposition of ball 85 can be adjusted, bothlongitudinally and rotationally, relative to sleeve 10, and hence thedisposition of ball 85 may be adjusted, both longitudinally androtationally, relative to a bone in which sleeve 10 is disposed. In thisway, the present invention provides a new joint prosthesis which permitsthe disposition of the ball to be adjusted, both longitudinally androtationally, relative to a socket.

If desired, a cage 90 (FIG. 9) may be mounted to the opposing side ofhead 45 (FIG. 1). By way of example but not limitation, a screw 91(FIG. 1) received in a hole 92 (FIG. 9) in cage 95 and a hole 93 (FIG.5) in head 45 may be used to secure cage 90 to head 45. The provision ofa cage on the prosthesis, preferably diametrically opposed to the ball,permits soft tissue or bone to be secured to the prosthesis, e.g., withsutures.

Also, if desired, openings 95 (FIG. 5) may be formed in center adapter35 (e.g., in head 45), in collar 65 and/or in cage 90, so as to receivea suture or a suture anchor, or like fastening element, whereby topermit soft tissue and/or bone to be secured to the joint prosthesis.

In use, sleeve 10 (preferably having collar 65 loosely secured thereto)is disposed in the intramedullary canal of a bone, center adapter 35(preferably having ball 85 secured thereto) is inserted into centrallumen 20 of the sleeve and is moved longitudinally and rotationally asneeded so as to present the ball for proper seating in the socket, andthen collar 65 is tightened (e.g., with screws 80) so as to securecenter adapter 35, and hence ball 85, in the desired longitudinal androtational position relative to sleeve 10, and hence in the desiredlongitudinal and rotational position relative to the socket.

Looking next at FIGS. 10-13, there is shown an alternative form of thenew joint prosthesis for replacing the ball of a ball-and-socket joint.The new joint prosthesis 105 of FIGS. 10-13 is generally similar to thejoint prosthesis 5 shown in FIGS. 1-9, except that (i) center adapter 35of FIGS. 1-9 is replaced by the center adapter 135 shown in FIGS. 10-13,and (ii) collar 65 of FIGS. 1-9 is replaced by the hinged collar 165shown in FIGS. 10-13.

More particularly, the center adapter 135 of FIGS. 10-13 issubstantially the same as the center adapter 35 of FIGS. 1-9, exceptthat the mount section 50 of center adapter 35 is replaced by the mountsection 150 of center adapter 135. In mount section 150, thehorizontally-extending slots 155 (FIG. 12) and thelongitudinally-extending slots 160 are effectively superimposed on oneanother, in the manner shown in FIG. 12.

In addition, the hinged collar 165 of FIGS. 10-13 comprises two halves166 which are hinged together by a pivot pin 167 rising out of sleeve10. A locking pin 168 (FIG. 10) is used to selectively lock the twohalves 166 together. At least one, and preferably both, of the twohalves 166 includes longitudinally-extending internal ribs 170 which areformed on a horizontally-extending internal rib 175. Thus, with theconstruction shown in FIGS. 10-13, the longitudinally-extending internalribs 170 are effectively superimposed on the horizontally-extendinginternal ribs 175.

It will be appreciated that, in this form of the invention, when the twohalves 166 of collar 165 are separated from one another, thehorizontally-extending internal ribs 175 and thelongitudinally-extending internal ribs 170 of collar 165 will beseparated from the horizontally-extending slots 155 and thelongitudinally-extending slots 160 of center adapter 135, and the centeradapter will be free to move longitudinally and rotationally relative tothe collar, and hence longitudinally and rotationally relative to thesleeve 10 to which the collar is mounted.

It will also be appreciated that, in this form of the invention, whenthe two halves 166 of collar 165 are locked together with locking pin168, horizontally-extending internal ribs 175 of collar 165 will seat inhorizontally-extending slots 155 in center adapter 135, andlongitudinally-extending internal ribs 170 of collar 165 will seat inlongitudinally-extending slots 160 of center adapter 135, whereby tolock center adapter 135 longitudinally and rotationally relative to thecollar, and hence to the sleeve 10 to which the collar is mounted.

Accordingly, in view of the foregoing construction, the disposition ofball 85 can be adjusted, both longitudinally and rotationally, relativeto sleeve 10, and hence may be adjusted, both longitudinally androtationally, relative to a bone in which sleeve 10 is disposed. In thisway, the present invention provides a new joint prosthesis which permitsthe disposition of the ball to be adjusted, both longitudinally androtationally, relative to a socket.

Looking next at FIGS. 14-20, there is shown another alternative form ofthe new joint prosthesis for replacing the ball of a ball-and-socketjoint. The new joint prosthesis 205 of FIGS. 14-20 is generally similarto the joint prosthesis 105 shown in FIGS. 10-13, except that the collar165 used in the construction of FIGS. 10-13 is replaced by a latchedcollar 265 as shown in FIGS. 14-20.

More particularly, latched collar 265 comprises two halves 266 pivotallymounted to the pivot pin 167 of sleeve 10. The two halves 266 of latchedcollar 265 are substantially the same as the two halves 166 of hingedcollar 165, except that the two halves 266 of latched collar 265 alsoeach comprise a latch mechanism 269 at its free end. Thus, at least one,and preferably both, of the two halves 266 includes ahorizontally-extending internal rib 275 carrying a plurality oflongitudinally-extending internal ribs 270 thereon. Accordingly, it willbe appreciated that with the construction shown in FIGS. 14-20, thelongitudinally-extending internal ribs 270 are again effectivelysuperimposed on the horizontally-extending internal ribs 275. Latchmechanisms 269 engage one another when the two halves 266 are broughttogether so that the two halves can catch to one another. A locking pin268 (FIG. 14) may be used to secure the two halves in their closedcondition.

It will be appreciated that, in this form of the invention, when the twohalves 266 of collar 265 are separated from one another, thehorizontally-extending internal ribs 275 and thelongitudinally-extending internal ribs 270 of collar 265 will beseparated from the horizontally-extending slots 155 and thelongitudinally-extending slots 160 of center adapter 135, and the centeradapter will be free to move longitudinally and rotationally relative tothe collar, and hence longitudinally and rotationally relative to thesleeve 10 to which the collar is mounted.

It will also be appreciated that, in this form of the invention, whenthe two halves 266 of collar 265 are locked together with locking pin268, horizontally-extending internal ribs 275 of collar 265 will seat inhorizontally-extending slots 155 in center adapter 135, andlongitudinally-extending internal ribs 270 of collar 265 will seat inlongitudinally-extending slots 160 of center adapter 135, whereby tolock center adapter 135 longitudinally and rotationally relative to thecollar, and hence to the sleeve 10 to which the collar is mounted.

Accordingly, in view of the foregoing construction, the disposition ofball 85 can be adjusted, both longitudinally and rotationally, relativeto sleeve 10, and hence may be adjusted, both longitudinally androtationally, relative to a bone in which sleeve 10 is disposed. In thisway, the present invention provides a new joint prosthesis which permitsthe disposition of the ball to be adjusted, both longitudinally androtationally, relative to a socket.

Looking next at FIGS. 21-25, there is shown another alternative form ofthe new joint prosthesis for replacing the ball of a ball-and-socketjoint. The new joint prosthesis 305 of FIGS. 21-25 is generally similarto the joint prosthesis 205 shown in FIGS. 14-20, except as willhereinafter be discussed.

More particularly, with the joint prosthesis 305 of FIGS. 21-25, collar265 is omitted and the sleeve 10 of FIGS. 14-20 is replaced by a newsleeve 310. Sleeve 310 comprises a plurality of horizontally-extendinginternal ribs 375 (FIGS. 23 and 25) which are separated from one anotherby bands of recessed wall 376. Each of the horizontally-extendingexternal ribs 375 carries a plurality of longitudinally-extendinginternal ribs 370 (FIG. 23) thereon. A threaded keyway 377 (FIG. 23) isformed in the side wall of sleeve 310. Threaded keyway 377 communicateswith central lumen 320 of sleeve 310.

In this form of the invention, the center adapter 135 of FIGS. 14-20 isreplaced by a new center adapter 335 (FIG. 22). Center adapter 335 issubstantially the same as the center adapter 135 of FIGS. 14-20, exceptthat center adapter 335 comprises a plurality of horizontally-extendingribs 378 which are separated from one another by bands of recessed wall379. Thus, the bands of recessed wall 379 essentially comprisehorizontally-extending slots in center adapter 335. Each of thehorizontally-extending ribs 378 carries a plurality oflongitudinally-extending slots 381 (FIG. 23) thereon.

And in this form of the invention, there is also provided a key lock 382which is radially movable along threaded keyway 377 via a screw 383.

As a result of this construction, and looking now at FIG. 25, when it isdesirable to adjust the position (either longitudinally or rotationally)of center adapter 335 relative to sleeve 310, key lock 382 is backed outalong threaded keyway 377, center adapter 335 is moved longitudinallyrelative to sleeve 310 as desired and then, in order to accommodaterotational adjustment, center adapter 335 is moved slightlylongitudinally if and as needed so as to align thehorizontally-extending ribs 378 of center adapter 335 with the bands ofrecessed wall 376 of sleeve 310 and so as to align the bands of recessedwall 379 of center adapter 335 with the horizontally-extending ribs of375 of sleeve 310, whereupon the rotational position of the centeradapter may be adjusted vis-à-vis the sleeve. Then center adapter 335 ismoved longitudinally slightly, so that the horizontally-extending ribs378 of the center adapter are aligned with the horizontally-extendingribs 375 of sleeve 310, with the longitudinally-extending internal ribs370 of sleeve 310 being received within the longitudinally-extendingslots 381 of center adapter 335. This action locks center adapter 335against rotational movement relative to sleeve 310. Then key lock 382 isadvanced along threaded keyway 377 via screw 383 until the inner end ofthe key lock engages one of the bands of recessed wall 379 in centeradapter 335. In other words, the distal end of key lock 382 projectsinto the horizontally-extending slot formed in the center adapter by theband of recessed wall 379 disposed between two adjacenthorizontally-extending ribs 378. This action locks center adapter 335against longitudinal movement relative to sleeve 310, since the innerend of key lock 382 engages the two horizontally-extending ribs 378 ofcenter adapter 335 which are disposed on either side of key lock.

Accordingly, it will be appreciated that, in view of the foregoingconstruction, the disposition of ball 85 can be adjusted, bothlongitudinally and rotationally, relative to sleeve 10, and hence thedisposition of ball 85 may be adjusted, both longitudinally androtationally, relative to a bone in which sleeve 10 is disposed. In thisway, the present invention provides a new joint prosthesis which permitsthe disposition of the ball to be adjusted, both longitudinally androtationally, relative to a socket.

It is also possible for the prosthesis to provide a socket, rather thana ball, at the free end of the center adapter.

Thus, for example, FIG. 26 shows a novel joint prosthesis 405 whichprovides a socket 485, rather than the head 45 and ball 85, at theproximal end of center adapter 135. In this respect it should also beappreciated that the joint prosthesis 405 shown in FIG. 26 comprises theaforementioned center adapter 135 (except modified to include socket485) in combination with the aforementioned sleeve 310, with key lock382 being used to selectively lock center adapter 135 to sleeve 310.Thus, in this form of the invention, rotational locking is provided byvirtue of the disposition of the longitudinally-extending internal ribs370 in the longitudinally-extending slots 160 of center adapter 135, andlongitudinal locking is provided by virtue of the disposition of the toeof key lock 382 in the horizontally-extending slots 155 in centeradapter 135.

By way of further example, FIGS. 27-29 show another novel jointprosthesis 405 which provides an alternative form of socket 486 at thedistal end of center adapter 135. If desired, a support collar 487 maybe provided between the top of sleeve 310 and the bottom of socket 486so as to provide increased support for the socket element. Furthermore,if desired, this support collar may be formed in two separate halves,united at the time of use, so as to facilitate deployment at thesurgical site.

Example Intended Use

The device and its associated method of use provide, in one exemplaryuse, a proximal humerus replacement prosthesis. The purpose of thisexemplary device is to replace the humeral head articular surface whenthe bone is damaged. These situations would include fractures and/ordislocation, aseptic necrosis or various forms of arthritis such asosteoarthritis, rheumatoid arthritis or post traumatic arthritis, failedjoint replacement or any other situation where arthrodesis or otherreconstructive procedures would not be expected to give a satisfactoryoutcome.

Design

The exemplary shoulder prosthesis system includes prosthetic componentsand instrumentation for the implantation of a modular proximal humerusreplacement. Some unique aspects of this system, among others, are thatit allows adjustment of the final prosthesis in height and rotation(version), i.e., longitudinally and rotationally, as well as havingspecial features to facilitate re-attachment of bone and soft tissue ifthat is desired. The height and version (i.e., the longitudinaldisposition and the rotational disposition) of the humeral prosthesisare critical factors in performing a shoulder replacement procedure.These variables are particularly difficult to measure in cases offracture or other situations of distorted anatomy such as asepticnecrosis or fracture malunion. These variables are normally measuredthrough a trialing process. However, in the setting of a fracture, it isvery difficult to secure the trial to the shaft of the humerus.Therefore the trial moves and shifts easily, making measurements veryinaccurate and hard to reproduce. Some alterations to the trial as wellas holding jigs have been tried with varying degrees of success. Patientsize and position also contribute to inaccuracy. Finally there is thedifficulty of making measurements based on landmarks that are fairlydistant such as the transcondylar axis at the distal humerus and forearmexternal rotation as references for prosthetic rotation. Adding to thedifficulty is the fact that once the final components are placed, eitherby cementing or in a press-fit fashion, there is no allowance foradjustment. The prosthesis position cannot be changed withoutsignificant structural risk to the shoulder bone stock. This causessignificant delays in the procedure as the surgeon checks and re-checksthe position of the trial, knowing that no changes can be made once thefinal prosthesis is secured in place.

The shoulder prosthesis system of the present invention, however, has adistinctive mechanism that simplifies the procedure and allows foradjustment of these critical factors with the final prosthesis. Theprocedure and method for placement of the shoulder prosthesis follows.The process of describing the procedure will also outline the key designfeatures of the system.

Procedure

The first step in the procedure is to prepare the humeral shaft. This isdone by reaming the intramedullary canal to create space for anddetermine the size of the initial component. This initial component is atubular sleeve with a flange-like collar at its top end, e.g., theaforementioned sleeve 310. See FIG. 30. Note that, the tubular sleeve310 shown in FIG. 30 is substantially the same as the sleeve 310disclosed above, except that the flange-like collar F shown in FIG. 30is not circular. More particularly, the flange-like collar F ispreferably extended radially outwardly in the portion containingthreaded keyway 377, whereby to make the key lock 382 disposed inthreaded keyway 377 more easily accessible to the surgeon.

The sleeve will be cemented into place in the same fashion as for allprosthesis of the shoulder. The sleeve is cemented fully seated down toits collar and need only be cemented in a position that allows access tothe key lock portion of the collar (described below). The sleeve'scollar is preferably protected by a separate cover (not shown) duringthe cementing procedure in order to prevent cement from getting into themechanisms on the collar which are used to secure the center adapter tothe collar. Once the cement is hardened and all extraneous cement isremoved, the protective cover is removed. It is into this sleeve thatthe prosthesis stem (e.g., the aforementioned center adapter 335) isplaced. See FIG. 31.

The sleeve diameter selected determines the corresponding prosthesisstem (e.g., center adapter) that will fit into the sleeve. Therefore,once the reaming is completed and determines the sleeve diameter, thatin turn determines the prosthesis stem (e.g., center adapter) that fitsthe sleeve. No further trialing is necessary inasmuch as the sleeve andstem (e.g., center adapter) are provided as a matched set.

The upper portion of the sleeve and the shaft of the prosthesis stem(e.g., center adapter) have a mechanism that allows the coupling of thetwo components but also allows adjustment for both height and rotation.See, for example, FIG. 32, which shows the aforementioned sleeve 310 andthe aforementioned center adapter 335. As discussed above, sleeve 310comprises a plurality of horizontally-extending internal ribs 375 whichare separated from one another by bands of recessed wall 376. Each ofthe horizontally-extending external ribs 375 carries a plurality oflongitudinally-extending internal ribs 370 thereon. A threaded keyway377 is formed in the side wall of sleeve 310. Threaded keyway 377communicates with central lumen 320 of sleeve 310. As also discussedabove, center adapter 335 comprises a plurality ofhorizontally-extending ribs 378 which are separated from one another bybands of recessed wall 379. Thus, the bands of recessed wall 379essentially comprise horizontally-extending slots in center adapter 335.Each of the horizontally-extending ribs 378 carries a plurality oflongitudinally-extending slots 381 thereon. And as also discussed above,the key lock 382 is radially movable along threaded keyway 377 via ascrew 383 so as to secure center adapter 335 in a desired positionrelative to sleeve 310.

All known current prostheses do not allow any significant adjustment ofthe prosthesis after the cement has hardened. However, since with thepresent invention a cylindrical sleeve is installed first, it provides afoundation from which the stem (e.g., center adapter) can be adjusted.It is the aforementioned coupling mechanism between the sleeve and thestem (e.g., center adapter) that allows this adjustment option. This isa tremendous advantage to the surgeon and patient as the position of thearticular surface can be optimized rather than having only one chance toestimate the proper position while cementing-in a final prosthesis thatis firmly fixed after the cement hardens.

From the foregoing disclosure, it will be appreciated that, in one formof the invention, the coupling mechanism entails a series of splines onthe shaft of the stem that match into corresponding splines on the upperportion of the sleeve. In one preferred form of the invention, there arethree levels of splines within the sleeve to engage three levels ofsplines on the stem (e.g., center adapter). Engaging three levels ofsplines creates strength in resisting rotational force and also thetop-to-bottom length of this engagement prevents toggle of the stem(e.g., center adapter) within the sleeve as well. These splines on eachcomponent are separated by a smooth recessed area. This smooth band ispreferably laser-marked black to assist in demonstrating properpositioning of the stem (e.g., center adapter) for adjustment andlocking options as described below. It will be appreciated that thedistance between the spline bands sets the increment of height change,and the number of splines determines the increment of rotationaladjustment. The coupling mechanism is preferably constructed so that itallows rotational adjustment in 10 degree increments and heightadjustment in 4 mm increments. The sleeve has a locking key that isdriven by a screw mechanism. As the screw is turned in a clockwisedirection, it drives the locking key toward the center of the sleeve.When the stem (e.g., center adapter) is aligned with a dark laser-markedsmooth area exposed immediately above the flange-like collar F, this isthe locking position. In this position, the splines on the stem (e.g.,center adapter) are engaged with the splines on the sleeve and a smootharea is aligned with the entry window of the locking key. As the lockingkey advances forward, it fits into the smooth area on the shaft of thestem (e.g., center adapter) below the first engaged spline at the top ofthe sleeve. With the locking key tightened into place, this holds theprosthesis stem (e.g., center adapter) within the sleeve, preventing anysuperior or inferior movement of the stem (e.g., center adapter). At thesame time, in this position, the splines are engaged as well, lockingthe prosthesis in rotation.

If adjustment is desired, then the key lock is backed up to disengagethe prosthesis stem (e.g., center adapter). The stem can then glidesuperiorly or inferiorly to adjust the height of the prosthesis. Ifrotational adjustment is desired, then the stem (e.g., center adapter)is held so one of the splines aligns with the superior rim of thesleeve. This puts the splines in alignment with the smooth bands andthus they do not engage. In this way rotation can be adjusted. When thedesired rotation is obtained, then the stem (e.g., center adapter) ismoved either superiorly or inferiorly so the splines engage at thedesired height. The key lock is advanced, with the stem (e.g., centeradapter) held in the locking position, and a laser-marked black smoothband aligned at the top edge of the sleeve.

When the final desired height and rotation are obtained, and the keylock is tightened into place, a locking cover 500 (FIG. 33) ispreferably applied to the sleeve so as to close off keyway 377. Thislocking cover fits into grooves which are formed within the window forthe key lock on the sleeve. See FIG. 33. The locking cover covers thekey lock, abutting against it and preventing back-out of the key lock.If the key lock cannot move backward, then the coupling mechanismremains secure. However, even at this stage, the locking cover 500 canbe easily removed from the sleeve and allow access to the key lock ifneeded. The locking cover 500 preferably has scallops at its superiorand inferior margins in order to accommodate a flat removal tool. Thisremoval tool can easily lever out the locking cover if furtheradjustment of the prosthesis is deemed necessary. Therefore the surgeoncan make adjustments to the prosthesis position at any time in theprocedure and is never at a point where this option is eliminated.

Re-attachment of soft tissue and bone are frequently needed in a jointrestoration procedure, particularly in the instance of a fracture. Thegreater and lesser tuberosity fragments have the tendons of the rotatorcuff muscles attached to them. They are usually re-attached by suturingthem to the prosthesis and the shaft of the bone. However, there is ahigh failure rate of the tuberosities uniting. Because a prosthesis ismade of metal, and while it is often coated with a substance to enhancehealing, it is difficult for fractured bone to heal to such a surface.This is made worse by the fact that there is frequently diminishedsurface area contact between the bone and such a surface. Someprostheses allow for some bone graft to be placed through a window inthe prosthesis to facilitate bone-to-bone healing. This has improvedtuberosity union rates, confirming that the concept is sound. However,the shape of such a bone plug in a small window on the prosthesis alsodoes not allow enough surface area to allow good opportunity forhealing.

To address this issue, the shoulder prosthesis of the present inventionpreferably has an optional bone cage that can be applied to the back ofthe prosthesis, e.g., the cage 90 previously discussed. See FIG. 34.This cage can be packed with bone graft or similar bone substituteand/or osteoconductive material. The windows of the bone cage are shapedand sized to maximize contact of the graft and the native bone beingapplied. The bone graft could be packed separately in a holding bowlthat could stabilize the cage. Once the bone graft is sufficientlypacked, it can be compressed with a tamp that is shaped like the backside of the prosthesis in order to ensure proper fit once the cage wasapplied to the prosthesis. With the graft packing completed, the cagecan then be applied to the prosthesis and secured with a screw, e.g.,screw 91. Significantly, because the bone cage is preferably shaped soas to follow the contours of the back of the prosthesis stem, the forceson the screw are dispersed. In addition, there is preferably a slightoffset between the threaded hole in the prosthesis (e.g., theaforementioned hole 93) and the hole in the back of the bone cage (e.g.,the aforementioned hole 92). As the screw fully seats, it places sometension on the bone cage. This tension, which places a lateral force onthe shaft of the screw, will prevent the screw from backing out. Thebone cage preferably also has multiple attachment points for suturing ofthe tuberosities to the prosthesis in order to ensure secure hold andapposition to the graft.

An additional feature that is present to enhance attachment of bone andsoft tissue to the prosthesis are optional suture anchors (FIG. 35) thatcan be placed in threaded holes on the prosthesis stem's head portion,e.g., the threaded holes 395 shown in FIG. 34. See, for example, FIG.36., which shows bone anchors (with attached suture) disposed in head45. These suture anchors can be placed anteriorly as well asposteriorly. Because the stem (e.g., center adapter) of the prosthesiscan be rotated and adjusted at any time, this allows access to theposterior aspect of the prosthesis for anchoring of the tuberosities ina fracture setting.

Normally, with the prosthesis fixed in place, it is very difficult toaccess the posterior aspect and all of the anchoring is applied to theanterior accessible aspect. These additional features increase thechoices available to the surgeon to achieve bony and soft tissue unionin this very difficult reconstructive environment. Because thesefeatures are optional, the surgeon can use them at his/her discretion toaddress the situation at hand.

Applicable Joints

It will be appreciated that the prosthesis of the present invention maybe used in a variety of joints within the body, e.g., the elbow, thewrist, the distal radius, proximal radius, hip, etc.

Modifications of the Preferred Embodiments

It should be understood that many additional changes in the details,materials, steps and arrangements of parts, which have been hereindescribed and illustrated in order to explain the nature of the presentinvention, may be made by those skilled in the art while still remainingwithin the principles and scope of the invention.

1. A joint prosthesis for mounting in a first bone and presenting aprosthetic joint surface for engaging an opposing joint surface of asecond bone, the joint prosthesis comprising: a sleeve which is adaptedfor partial disposition in an opening formed in the first bone; a centeradapter which is adapted for disposition within the sleeve; and aprosthetic joint surface mounted to the center adapter; wherein thedisposition of the center adapter is adjustable, both longitudinally androtationally, relative to the sleeve, so that the disposition of theprosthetic joint surface is adjustable, both longitudinally androtationally, relative to the opposing joint surface of the second bone.2. A joint prosthesis according to claim 1 wherein the opening comprisesthe intramedullary canal of the first bone.
 3. A joint prosthesisaccording to claim 1 wherein the joint surface comprises a convexsurface.
 4. A joint prosthesis according to claim 3 wherein the jointsurface comprises a hemispherical structure.
 5. A joint prosthesisaccording to claim 4 wherein the hemispherical structure comprises theball of a ball-and-socket joint.
 6. A joint prosthesis according toclaim 1 wherein the joint surface comprises a concave surface.
 7. Ajoint prosthesis according to claim 6 wherein the joint surfacecomprises a socket.
 8. A joint prosthesis according to claim 7 whereinthe socket comprises the socket of a ball-and-socket joint. 9.(canceled)
 10. A joint prosthesis according to claim 9 wherein thesleeve comprises a first body and a second body, wherein the first bodycomprises the central lumen and the second body comprises thehorizontally-extending rib and the longitudinally-extending rib, andfurther wherein the second body is selectively securable to the firstbody.
 11. A joint prosthesis according to claim 10 wherein the firstbody of the sleeve comprises a crown having a peripheral detent formedtherein, wherein the second body of the sleeve comprises a collar havinga nib formed thereon, and further wherein the second body of the sleeveis secured to the first body of the sleeve when the nib is disposed inthe peripheral detent.
 12. A joint prosthesis according to claim 11wherein the second body of the sleeve comprises two halves selectivelysecured together.
 13. A joint prosthesis according to claim 10 whereinthe longitudinally-extending rib is formed on the horizontally-extendingrib.
 14. A joint prosthesis according to claim 13 wherein the first bodyof the sleeve comprises the central lumen and the second body of thesleeve comprises the horizontally-extending rib and alongitudinally-extending rib, and further wherein the second body of thesleeve is selectively securable to the first body.
 15. A jointprosthesis according to claim 13 wherein the second body of the sleevecomprises two halves pivotally secured to the first body.
 16. A jointprosthesis according to claim 13 wherein the two halves latch to oneanother.
 17. A joint prosthesis according to claim 13 wherein theplurality of horizontally-extending slots of the center adapter and theplurality of longitudinally-extending slots of the center adapter aresuperimposed upon one another. 18.-22. (canceled)
 23. A joint prosthesisaccording to claim 1 wherein the joint prosthesis further comprises acage mounted to the center adapter.
 24. A joint prosthesis according toclaim 1 wherein the joint prosthesis further comprises an opening forreceiving a suture anchor therein.
 25. A method for restoring a joint,the method comprising: providing a joint prosthesis for mounting in afirst bone and presenting a prosthetic joint surface for engaging anopposing joint surface of a second bone, the joint prosthesiscomprising: a sleeve which is adapted for disposition in an openingformed in the first bone; a center adapter which is adapted for partialdisposition within the sleeve; and a prosthetic joint surface mounted tothe center adapter; wherein the disposition of the center adapter isadjustable, both longitudinally and rotationally, relative to thesleeve, so that the disposition of the prosthetic joint surface isadjustable, both longitudinally and rotationally, relative to theopposing joint surface of the second bone; forming an opening in thefirst bone; deploying a sleeve in the opening formed in the first bone;positioning a center adapter partially within the sleeve; adjusting thelongitudinal and rotational position of the center adapter with respectto the sleeve; and securing the center adapter to the sleeve.